The present invention relates generally to signal generators and more particularly to a signal generation system having a plurality of signal generators coupled via a cable(s) that can automatically adjust phases between outputs of the signal generators when the frequency of the sampling clock is changed.
A signal generator produces an electronic signal corresponding to arbitrary waveform data that may be set by a user. The electronic signal may be applied to a circuit under test to confirm the proper operation of the circuit. The circuit under test generates an output signal in response to the input test signal which is measured with an oscilloscope. The AWG7000 series of Arbitrary Waveform Generators, manufactured by Tektronix, Inc., Beaverton, Oreg., USA, are examples of signal generators that generate electronic signals in response to arbitrary waveform data stored in the signal generator.
A signal generator typically has two or four output channels. If more channels are required a plurality of signal generators may be used at a time. It is important when using the outputs of multiple signal generators to align phases between the outputs of the generators. In a conventional method of aligning phases between the outputs of signal generators, one of the signal generators may be assigned as the master and provide a reference oscillation signal to an external distribution amplifier that amplifies the reference oscillation signal to provide to other signal generators (slaves) for operating in a phase locked and coherent mode at a common frequency as described in: “PSG Signal Generators Brochure”, by Agilent Technologies, Inc., USA disclosing that the E8267D PSG Vector signal generators provide phase locked signals using the Z5623AK05 Distribution Amplifier, URL: http://cp.literature.agilent.com/litweb/pdf/5989-1324EN.pdf.
Signal generator may have a trigger function that initiates the start of the signal output according to a given signal provided from an external circuit, user operation through an operation panel, or the like. The signal generator may also have an event function that changes the type of the output signal according to a given signal provided from an external circuit, user operation through the operation panel, or the like. When the trigger and/or event functions start and/or change the output signal, it is necessary to keep the phase relationship between the outputs of the signal generators.